This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


Re: [Xen-devel] serial ports in a pv domU

xen-devel-bounces@xxxxxxxxxxxxxxxxxxx wrote on 03/19/2010 03:36:57 PM:

> xen-devel-bounces@xxxxxxxxxxxxxxxxxxx wrote on 03/19/2010 01:29:22 PM:
> > On Fri, 2010-03-19 at 17:21 +0000, Michael D Labriola wrote:
> > > Is there a way to pass a system's on-board serial port(s) into a 
> > > paravirtualized domU?
> > 
> > I think you can pass individual IO ports and interrupt through to a PV
> > guest without necessarily passing through a PCI device. 
> > 
> > I'm afraid I don't actually know the exact runes to cause xend or xl 
> > whatever to do this though -- I think perhaps for xend lines like:
> >    ioport=03f8-03f9
> >    irq=3
> > (or whatever the com port uses) in your config file might do the 
> > 
> > > I don't have any on hand to test with, but would passing a PCI 
> card 
> > > into the domU have any issues?
> > 
> > I'd expect that to work alright.
> Hmm, thought I had this working.  With 'ioports = ['3f8-3ff']' and 
> 'irq=[4]' in my cfg file, I get appropriate messages in domU's dmesg 
> initializing ttyS0...  But the device doesn't seem to work.  And the 
> device still works in dom0...
> I looked at the old InstallationNotes Wiki (last touched Nov 2007?) 
> says to blacklist the 8250, 8250_pnp, and serial_core modules... is this 

> still needed with the pv_ops kernels?  Pretty sure I've got the serial 
> stuff compiled into the kernel, so I can't really blacklist those unless 
> recompile.  I tried unbinding the devices from their driver via sysfs, 
> then the devices don't show up in domU at all...

Odd... after breaking everything by manually unbinding from the serial 
driver, I rebooted.  And now my domU has ttyS0 and it actually works.

Michael D Labriola
Electric Boat
401-848-8871 (desk)
401-848-8513 (lab)
401-316-9844 (cell)

Xen-devel mailing list

<Prev in Thread] Current Thread [Next in Thread>